Tribological performance of thermoplastic composites via thermally conductive material and other fillers and a process for making the composite and molded articles of the same

ABSTRACT

This thermoplastic composition and process for making articles of the same includes a thermoplastic matrix that includes a resin and filler materials wherein the filler materials includes a combination of fibers, at least one lubricant, and thermally conductive material, for improving tribological performance of thermoplastic materials. In the alternative, a thermally conductive lubricant may be substituted for the combination of the lubricant and the thermally conductive material.

TECHNICAL FIELD

[0001] This invention relates generally to thermoplastic polymers and,in particular, to improving the tribological performance ofthermoplastic polymers via thermally conductive media and other fillersand a process for making the same.

BACKGROUND ART

[0002] There has been a need for high performance reinforced plasticcompositions having enhanced performance capabilities, from a standpointof durability and longevity, when exposed to wear mechanisms encounteredin a typical tribological environment. Such compositions generally havea unique combination of reinforcement materials incorporated into aplastic material.

[0003] Bearing materials comprised of self-lubricating compositionmaterial prepared from polymers have become popular in the friction andlubrication field because they are self-lubricating, rust-resistant,light in weight, easy to fabricate, relatively low in cost and verycompatible. A large percentage of conventional metal bearing membershave been gradually replaced by bearing members made from materialsusing polymers as a matrix.

[0004] An engine driveline is one example of a tribological environmentwhere the use of plastic components for dynamic sealing and bearingapplications is well known. In this environment, i.e., where a sealingor bearing interface is involved, the plastic component is exposed tofriction, pressure, high temperature and lubricants. One such dynamicplastic component is a thrust washer, which is constantly subjected to acombination of varying levels of speed and load at high temperatures.Typically, a multiple of pressure and relative velocity (P*V) is used asa measure of how rigorous and demanding the application is. For example,a P*V value can range from as low as 50,000 to as high as 1,250,000, thepressure being measured in pounds/square-inch (p.s.i.) and the velocitybeing measured in feet/minute (f.p.m.). Applications having a P*Vgreater than 150,000 are generally considered to be very demanding.

[0005] When a thrust washer is used in a dynamic bearing application, iteventually fails either due to excessive wear at a given P*V, or highthermal stresses due to poor heat dissipation, e.g., “hot spotting”, orsometimes a combination of both. Thus it is very desirable that thethrust washer has a high wear resistance at a given P*V so that itperforms as a bearing, that it has good dissipation properties to avoidthermal stresses and that it has good flexibility to provide toughnessand perform as a bearing. Thrust washers are typically made fromplastics such as polyethersulphone (PES), polyamides (PA),polyaryletherketone (PAEK) and polyphenylenesulphides (PPS), to name afew. It would be advantageous to have a lower cost alternative to thePAEK-based thermoplastic bearing materials currently used in dynamicplastic components, including thrust washers.

[0006] Besides thrust washers, there are engine parts that are alsoexposed to tribological wear mechanisms. Sleeve bearings made fromplastic compositions are constantly subjected to a harsh environment dueto elevated temperatures encountered in the engine, as well asfrictional wear and lubricants. Seal rings made from plasticcompositions perform the dual function of a seal and a bearing and thusrequire a combination of high wear resistance and weld line strengthwithout a significantly high flexural modulus.

[0007] It is desirable to have a thermoplastic composition that hasexcellent wear resistance and weld line strength properties without asignificant increase in the flexural modulus. In addition, it would bedesirable to have such a thermoplastic composition that is relativelyinsensitive to increases in load, has a medium for maintaining itstemperature below its glass transition temperature, and exhibitsexcellent chemical resistance.

[0008] Furthermore, it is desirable to have a thermoplastic compositionwith the above qualities that is available at a lower price thancomparable thermoplastic bearing materials currently on the market.

[0009] The present invention is directed to overcoming one or more ofthe problems set forth above.

DISCLOSURE OF THE INVENTION

[0010] In one aspect of this invention, a thermoplastic composition isdisclosed. This thermoplastic composition includes a thermoplasticmatrix that includes a resin and filler materials wherein the fillermaterials includes a combination of fibers, at least one lubricant, andthermally conductive material, for improving tribological performance ofthermoplastic materials. In the alternative, a thermally conductivelubricant may be substituted for the combination of the lubricant andthe thermally conductive material.

[0011] In another aspect of the present invention, a process for forminga product that functions in a tribological environment that includes thesteps of compounding and molding a thermoplastic composition including athermoplastic matrix that includes a resin and filler materials whereinthe filler materials includes a combination of fibers, at least onelubricant, and thermally conductive material, for improved tribologicalperformance of thermoplastic materials at lower cost. In an alternative,a thermally conductive lubricant may be substituted for the combinationof the lubricant and the thermally conductive material.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] For a better understanding of the present invention, referencemay be made to the accompanying drawings in which:

[0013]FIG. 1 is a graph illustrating the torque response of a preferredembodiment of the present invention during high speed, low load P*Vtesting conditions;

[0014]FIG. 2 is a graph illustrating the temperature response of thepreferred embodiment during high speed, low load P*V testing conditions;

[0015]FIG. 3 is a graph illustrating the wear test results of thepreferred embodiment during high speed, low load P*V testing conditions;

[0016]FIG. 4 is a graph illustrating the volumetric wear rate for thepreferred embodiment at various system temperatures;

[0017]FIG. 5 is a graph illustrating wear test results for the preferredembodiment and a known sample composite aged in 120° C. transmission oilfor 4,000 hours;

[0018]FIG. 6 is a graph illustrating wear test results for the preferredembodiment and a known sample composite aged in 120° C. air for 4,000hours;

[0019]FIG. 7 is a graph illustrating wear test results for the preferredembodiment and a known sample composite aged in 20° C. kerosene for2,000 hours;

[0020]FIG. 8 is a graph illustrating wear test results for the preferredembodiment and a known sample composite aged in 20° C. water for 100hours;

[0021]FIG. 9 is a graph illustrating a comparison of the tensilestrength and tensile elongation of the preferred embodiment and a knownsample composite;

[0022]FIG. 10 is a graph illustrating a comparison of the flexuralstrength and flexural modulus of the preferred embodiment and a knownsample composite;

[0023]FIG. 11 is a graph illustrating the preferred embodiment'sretention of tensile strength and tensile elongation after aging in 120°C. transmission fluid for 2000 hours;

[0024]FIG. 12 is a graph illustrating the preferred embodiment'sretention of tensile strength and tensile elongation after aging in 120°C. air for 4,000 hours;

[0025]FIG. 13 is a graph illustrating the preferred embodiment'sretention of tensile strength and tensile elongation after aging in 20°C. water for 500 hours;

[0026]FIG. 14 is a graph illustrating the preferred embodiment'sretention of tensile strength and tensile elongation after aging in 20°C. kerosene for 500 hours;

[0027]FIG. 15 is a graph illustrating the preferred embodiment'sretention of flexural strength and flexural modulus after aging in 120°C. transmission fluid for 2,000 hours;

[0028]FIG. 16 is a graph illustrating the preferred embodiment'sretention of flexural strength and flexural modulus after aging in 120°C. air for 4,000 hours;

[0029]FIG. 17 is a graph illustrating the preferred embodiment'sretention of flexural strength and flexural modulus after aging in 20°C.water for 500 hours; and

[0030]FIG. 18 is a graph illustrating the preferred embodiment'sretention of flexural strength and flexural modulus after aging in 20°C. kerosene for 500 hours.

BEST MODE FOR CARRYING OUT THE INVENTION

[0031] In the preferred embodiment of the present invention, acombination of fibers, at least one lubricant, and thermally conductivematerial is incorporated into a thermoplastic matrix, resulting in areinforced thermoplastic composition material for forming molded andextruded products that function in a tribological environment. Athermally conductive lubricant can be substituted for the combination ofat least one lubricant and thermally conductive material.

[0032] The thermoplastic matrix that holds the solid lubricants andreinforced fibers includes a resin. This resin is preferablysemi-crystalline. The thermoplastic composition has a glass transitiontemperature that typically, but not necessarily, exceeds a bulk systemtemperature of the surfaces of mating components in a tribologicalenvironment, in the absence of frictional heating. Preferably, the glasstransition temperature is at least 70° C., advantageously over 90° C.,and preferably about 125° C.

[0033] One suitable base resin material is a thermoplastic copolymer ofan aliphatic-aromatic polyamide and a terephthalic aromatic chain havinga trade name “Zytel HTN FE8200.” Zytel HTN FE8200 is a semi-crystallineengineering resin manufactured by E. I. du Pont de Nemours and Company,which has its corporate headquarters at 1007 Market Street, Wilmington,Del. 19898. In addition, Zytel HTN FE8200 has a glass transitiontemperature of 125° C. and a melting point of 300° C. Zytel HTN FE8200also has a higher melting point, a higher glass transition temperature,and a higher tensile strength than many other polyamide resins or higherperformance polymers. Furthermore, Zytel HTN FE8200 is a member of thenylon family. Nylons display a low coefficient of friction when theycontact many other materials. Also, when used within their P*Vlimitations, nylons have good resistance to wear. It is well known inthe art that this base resin can be filled with long glass reinforcementfor use in high temperature and structural applications. However, thepreferred embodiment advantageously uses non-glass-filled Zytel HTNFE8200 as the matrix for a bearing material.

[0034] The base resin material present in the thermoplastic compositionpreferably comprises from about 50% to about 95% by weight of thethermoplastic composition with the optimal value being about 75%.

[0035] The thermoplastic matrix may also be comprised of the base resinof polyphthalamide. For example, polyphthalamide is a semi-crystallineresin that has a glass transition temperature of 105° C. and a meltingpoint of 310° C. Grades of polyphthalamide provide significantlyimproved toughness comparable to other polymers and retain much higherstrength and stiffness across a broad humidity and temperature range.

[0036] Yet another base resin material that the thermoplastic matrix mayinclude is polyphenylene sulfide. Polyphenylene sulfide is a specialtyengineering plastic recognized for its unique combination of properties,including thermal stability and chemical resistance. Polyphenylenesulfide has a glass transition temperature of 85° C. and a melting pointof 285° C.

[0037] Other resins with relatively high glass transition temperaturesmay also be used for the thermoplastic matrix. Any resin, however, musthave at least a glass transition temperature that exceeds a bulk systemtemperature of the surrounding tribological environment. For example,Nylon 4, 6, which has a glass transition temperature of 82° C., andliquid crystal polymers are two additional base resins which thethermoplastic matrix may comprise.

[0038] The filler material contained in the thermoplastic matrix caninclude a combination of fibers, to impart an optimum combination ofdesirable properties such as wear resistance and compressive strengthwithout significant increase in flexural modulus, and lubricants toimpart the required amounts of lubricity to the thermoplastic.

[0039] In a preferred embodiment of the present invention, the fiberused in the filler material is milled glass fiber. Using milled glassfiber is advantageous because it conveniently has many exposed fiberends and a small percentage of milled glass fiber imparts a significantamount of wear resistance. Milled glass fiber also advantageously servesto moderately “machine” a mating surface.

[0040] The milled glass fiber used to carry out a preferred embodimentof the present invention has the trade name Fiberglas® brand milledfibers 497DB and is manufactured by Owens Corning, that has itsheadquarters located at One Owens Corning Parkway, Toledo, Ohio 43659.

[0041] Fibers are present in the thermoplastic matrix, preferablycomprising in a range from about 0% to about 35% of the thermoplasticcomposition with the most preferred value being 5%. Furthermore, thefibers have a length desirably in the range from about 50 to about 2500micrometers, a diameter in the range from about 50 to about 200micrometers, and a length to diameter ratio of about 1:20.

[0042] Numerous other fibers or fiber-like substances may be utilized,including but not limited to, glass, aramid, carbon, and ceramic.

[0043] Certain lubricants are advantageously added to the thermoplasticmatrix of the embodiment to impact the required amount of lubricity tothe composition. Some preferred lubricants includepolytetrafluoroethylene, silicone resin modifier, and metallicparticles. The preferred type of metallic particles are bronze flakes.

[0044] Polytetrafluoroethylene advantageously imparts lubricity to thethermoplastic composition and is present in the thermoplastic matrix,preferably comprising in a range from about 0% to about 20% by weight ofthe thermoplastic composition, with the most preferred value being 5%.The polytetrafluoroethylene used in carrying out a preferred embodimenthas the trade name WHITCOM PTFE TL-5, is manufactured by ICIFluropolymers and is well known in the art as a common ingredient inself-lubricated thermoplastic bearing compositions. ICI has an addressat 1300 Connecticut Avenue NW., Suite 901, Washington D.C. 20036.

[0045] Silicone resin modifiers are known as a processing aid to be usedwith low temperature resins. However, a preferred embodiment of thepresent invention advantageously utilizes an unusually higher percentageof silicone resin modifier as a composition bearing additive. Siliconeresin modifier conveniently imparts lubricity, aids in processing, andgives the thermoplastic flame retardance. A preferred silicone resinmodifier has the trade name Silicone Resin Modifier 4-7051, ismanufactured by Dow Corning, located at 2200 W. Salzburg Road, MidlandMich. 48686, and is present in the thermoplastic matrix, preferablycomprising from about 0% to about 20% by weight of the thermoplasticcomposition, with the most preferred value being 5%.

[0046] Metallic particles are known for use in sinterable fluoropolymercompositions as a thermally conductive agent. A preferred embodiment ofthe present invention synergistically uses bronze flakes to channel heatgenerated at the interface through the bearing and also to impartlubricity. The bronze flake used to carry out a preferred embodiment hasa trade name Bronze Flake 9020, is manufactured by Reade AdvancedMaterials. Reade Advanced Materials has an address at Post Office Drawer15039, Riverside, R.I. 02915-0039. Metallic particles are present in thethermoplastic matrix, preferably comprising in a range from about 2% toabout 30% by weight of the thermoplastic composition, with the mostpreferred value being 10%. The size of the metallic particles can rangefrom 0.01 micrometers to about 50 micrometers with the optimal size ofaround 12.57 micrometers.

[0047] Tribological performance data for the thermoplastic compositionbearing material of a preferred embodiment of the present invention isshown in FIGS. 1 and 2. FIG. 1 shows the torque response for theembodiment. The P*V is varied by changing the speed and load inputs. Theapproximate P*V levels for each step are shown at the bottom of thegraph, ranging from 100,000 p.s.i.*f.p.m. to 300,000 p.s.i.*f.p.m. Inputspeed and load, are denoted as high, medium, and low. The resultanttorque reading for the system is shown by a star for known samples andby a circle for the preferred embodiment of the present invention.

[0048]FIG. 1 shows that the present invention is much more insensitiveto increases in load than the known samples. Furthermore, even as thelubricant film is squeezed out at higher loads, the lubricity of thecomposition does not allow a significant increase in the coefficient offriction.

[0049]FIG. 2 shows the temperature response of the thermoplasticcomposition. Input speed and load, denoted by high, medium, and low arelisted along the x-axis. The resultant average interfacial temperaturereading for the system is shown by a star for a known sample and by acircle for the preferred embodiment of the present invention. Also, asshown in FIG. 2, the average interfacial temperature remains below 120°C. because there is no appreciable increase in the coefficient offriction. However, even if the coefficient of friction were to rise athigh loads, higher than that shown in FIG. 2, the thermal conductivityof the resin would advantageously help function as a means to channelthe heat away from the interface and delay the onset of acceleratedwear.

[0050] In a test where the splash lubricant was removed and the load wascontinually increased, the interface temperature of a PAEK-basedthermoplastic bearing material increased past its glass transitiontemperature and caused failure within twenty-four minutes. However,under the same conditions, a preferred embodiment of the presentinvention lasted for almost two hours before system failure. Thisdemonstrates the superior performance of the present invention.

[0051] Testing was also conducted to determine the P*V capability of apreferred embodiment at a constant speed of 1800 rpm, while continuallyincreasing load. This test showed that the PAEK-based bearing materialexhibited catastrophic interface temperatures at a pressure of 300p.s.i., resulting in a P*V limit of 336,000 p.s.i.*f.p.m. under theseconditions. The preferred embodiment tested showed no appreciableincrease in interface temperature up to a pressure of 500 p.s.i., (thelimit of the test) resulting in a P*V capability of at least 560,000p.s.i.*f.p.m. under the conditions tested. This confirms the superiorperformance of the preferred embodiment.

[0052] Wear tests were also conducted to determine the wear resistanceof a preferred embodiment of the present invention. FIG. 3 shows acomparison of the embodiment's wear depth, compared to that of othermore expensive plastic bearing materials after a 100 hour wear testconducted at a p*v of 205,000 p.s.i.*f.p.m. under splash lubricatedconditions. As shown on FIG. 3, the wear test shows that the preferredembodiment meets the pre-set requirement that it performs at least aswell as other, more expensive transmission thrust washer materials, withthe sole exception of a composition formed of a self-lubricated,PAEK-based thermoplastic bearing material. However, the performance ofthe preferred embodiment is nearly as good as that of that of theself-lubricated, PAEK-based thermoplastic bearing material.

[0053] The preferred embodiment of the present invention is alsolubricious enough to prevent detrimental frictional heat in lubricatedtribological contacts at normal system temperatures in the range of 70°C. to 100° C. However, because heat may evolve in a transmission from anexternal source, testing was conducted to determine the tribologicalresponse at excessive system temperatures. Upon completion of a test runat a system temperature of 132° C., the known sample composition showedcatastrophic failure due to melting at a P*V level in the range fromabout 392,000 to about 448,000 p.s.i.*f.p.m. The preferred embodimenttested under the same conditions, does not show any signs of melting.Furthermore, the wear depth for the sample thrust washer comprised ofthe preferred embodiment had a wear depth of only 0.017 millimeters.

[0054] Additional testing was performed by exposing a washer made from apreferred embodiment of the present invention to a 132° C. oil deliverytemperature at 205,000 P*V for 100 hours. The resulting wear rate of0.00263 cubic centimeters per hour (cm³/hr) indicates that the samplecould run for over 800 hours at these conditions. The volumetric wearrate for the present invention at various system temperatures is shownin FIG. 4.

[0055] For a preferred embodiment of the present invention having anylon-based copolymer base resin, testing was necessary to evaluate thepotential effect of aging on physical and tribological properties. Atypical example of a tribological component is, but is not limited to, atransmission thrust washer. A transmission thrust washer is commonlyexposed to hot air and transmission oil, and could also be exposed towater and kerosene. Therefore, testing was conducted to see how thenylon-based copolymer would perform when exposed to these conditionsover time. Tribological results from a 4,000 hour aging test, comparingthe wear of the embodiment to the wear of the known sample composition,are shown in FIGS. 5-8.

[0056]FIG. 5 shows the wear test results for samples of a preferredembodiment of the present invention aged in 120° C. transmission oil for4,000 hours. FIG. 6 shows the wear test results for samples aged in 120°C. air for 4000 hours. FIG. 7 shows the wear test results for samplesaged in 20° C. Kerosene for 2,000 hours. FIG. 8 shows the wear testresults for samples aged in 20° C. water for 100 hours. The results fromthe tests, as reflected in FIGS. 5-8, demonstrate the preferredembodiment's excellent chemical resistance and its superior performanceover time, when subjected to adverse operating conditions.

[0057] The preferred embodiment of the present invention also exhibitssuperior weld line strength. Weld line strength can be described as ameasure of the flexural strength of a thrust washer across its weldline. It is often expressed as a percent of parent material anddesignated as weld line strength retention. The preferred embodiment ofthe present invention exhibits a weld line strength retention of over90%, which is considered excellent. Weld line strength is importantbecause if the washer were to break in a transmission, it would be muchmore likely to fall from the gear-carrier interface and cause excessivewear between the gear and the carrier as well as other transmissionproblems.

[0058] The physical properties for bearing materials used in thrustwashers need to be of adequate strength to support the compressiveloading on the washers and to withstand the minimum flexing due to awavy mating surface. FIG. 9 compares the tensile strength and tensileelongation of a preferred embodiment of the present invention with thatof the known sample composition. FIG. 10 compares the flexural strengthand flexural modulus of the preferred embodiment with that of the knownsample composition. Those skilled in the art can see from FIGS. 9 and 10that the preferred embodiment's tensile strength and flexural strengthare more than adequate for most bearing applications.

[0059] It is well known in the art that aging samples and noting theirphysical property retention after their exposure to particular fluidsover time is beneficial. Normally, if physical properties are retainedat levels of 90% or better, the material's resistance to chemical attackunder those conditions would be considered excellent. A preferredembodiment of the present invention was tested by aging in hottransmission oil, hot air, kerosene and water for up to 4,000 hours.

[0060] The tensile properties of a preferred embodiment of the presentinvention at various time intervals are shown in FIGS. 11-14. FIG. 11 isa graph illustrating the preferred embodiment's retention of tensilestrength and tensile elongation after aging in 120° C. transmissionfluid for 2000 hours. FIG. 12 is a graph illustrating the preferredembodiment's retention of tensile strength and tensile elongation afteraging in 120° C. air for 4,000 hours. FIG. 13 is a graph illustratingthe preferred embodiment's retention of tensile strength and tensileelongation after aging in 20° C. water for 500 hours. FIG. 14 is a graphillustrating the preferred embodiment's retention of tensile strengthand tensile elongation after aging in 20° C. kerosene for 500 hours. Asseen in FIGS. 11-14, the preferred embodiment showed excellent chemicalresistance under these conditions, retaining its tensile properties at alevel above 90% under each of the testing conditions.

[0061] The flexural properties of a preferred embodiment at various timeintervals are shown in FIGS. 15-18. FIG. 15 is a graph illustrating theretention of flexural strength and flexural modulus after aging in 120°C. transmission fluid for 2,000 hours. FIG. 16 is a graph illustratingthe retention of flexural strength and flexural modulus after aging in120° C. air for 4,000 hours. FIG. 17 is a graph illustrating theretention of flexural strength and flexural modulus after aging in 20°C. water for 500 hours. FIG. 18 is a graph illustrating the retention offlexural strength and flexural modulus after aging in 20° C. kerosenefor 500 hours. Under each testing condition, all flexural propertieswere maintained at levels above 90%, with one exception. When exposed to120° C. air for 4000 hours, the preferred embodiment of the presentinvention showed only a 70% retention of its flexural strength. This, incombination with the sample's failure mode, indicates that the materialwas becoming slightly more brittle. It is unlikely that the materialwould become more brittle upon further exposure to hot air. Furthermore,the flexural property retention was still in an acceptable range, asthrust washers do not see much flex in their application and thetribological properties of the present invention do not catastrophicallyworsen under these conditions.

[0062] Industrial Applicability

[0063] The present invention is a thermoplastic composition that isadvantageously applicable in a tribological environment. Thethermoplastic composition according to the present invention can beuseful in a variety of applications where a combination of wearresistance and weld line strength is desirable without a significantincrease in the flexural modulus. Furthermore, the present embodiment isuseful for high performance plastic components in applications where asealing or bearing interface is involved and where the plastic componentis exposed to friction, pressure, high temperature and lubricants. Thus,the present embodiment is particularly useful for making thrust washers,pump seals, sleeve bearings and other dynamic bearing and sealingcomponents for engines and transmissions.

[0064] Also, the raw material cost of the preferred embodiment of thepresent invention is significantly lower than the raw material cost ofthe thermoplastic bearing materials well known in the art for similarand identical applications.

[0065] The following description is only for the purposes ofillustration and is not intended to limit the present invention as such.It will be recognizable, by those skilled in the art, that the presentinvention is suitable for a plurality of other applications.

[0066] In view of the foregoing, it is readily apparent that the subjectthermoplastic composition provides a superior and cost-effectivematerial that very effectively functions within a tribologicalenvironment.

[0067] Other aspects, objects and advantages of the present inventioncan be obtained from a study of the drawings, the disclosure and theappended claims.

1. A thermoplastic composition, comprising a thermoplastic matrix thatincludes a resin and filler materials wherein said filler materialsincludes a combination of fibers, at least one lubricant, and thermallyconductive material, for improving tribological performance ofthermoplastic materials.
 2. The thermoplastic composition according toclaim 1, wherein said thermoplastic composition has a glass transitiontemperature that exceeds a bulk system temperature of surfaces of matingcomponents in a tribological environment, in the absence of frictionalheating.
 3. The thermoplastic composition according to claim 1, whereinsaid resin is semi-crystalline.
 4. The thermoplastic compositionaccording to claim 3, wherein said semi-crystalline resin is in a rangefrom about 50% to about 95% by weight of the thermoplastic composition.5. The thermoplastic composition according to claim 1, wherein saidlubricant includes polytetrafluoroethylene.
 6. The thermoplasticcomposition according to claim 1, wherein said lubricant includessilicone resin modifier.
 7. The thermoplastic composition according toclaim 1, wherein said thermally conductive material includes metallicparticles.
 8. The thermoplastic composition according to claim 7,wherein said metallic particles include bronze flakes.
 9. Thethermoplastic composition according to claim 1, wherein said lubricantincludes polytetrafluoroethylene and silicone resin modifier.
 10. Thethermoplastic composition according to claim 1, wherein said lubricantincludes polytetrafluoroethylene and said thermally conductive materialincludes metallic particles.
 11. The thermoplastic composition accordingto claim 1, wherein said lubricant includes silicone resin modifier andsaid thermally conductive material includes metallic particles.
 12. Thethermoplastic composition according to claim 1, wherein said lubricantincludes polytetrafluoroethylene and silicone resin modifier and saidthermally conductive material includes metallic particles.
 13. Thethermoplastic composition according to claim 5, wherein saidpolytetrafluoroethylene is in a range from about 0% to about 20% byweight of the thermoplastic composition.
 14. The thermoplasticcomposition according to claim 6, wherein said silicone resin modifieris in a range from about 0% to about 20% by weight of the thermoplasticcomposition.
 15. The thermoplastic composition according to claim 7,wherein said metallic particles are in a range from about 2% to about30% by weight of the thermoplastic composition.
 16. The thermoplasticcomposition according to claim 15, wherein each of said metallicparticles range in size from about 0.01 micrometers to about 50micrometers.
 17. The thermoplastic composition according to claim 1,wherein said fibers are selected from a group that includes glass,aramid, carbon, and ceramic.
 18. The thermoplastic composition accordingto claim 1, wherein said fibers are in a range from about 0% to about35% by weight of the thermoplastic composition.
 19. The thermoplasticcomposition according to claim 1, wherein said fibers each have a lengthin a range from about 50 micrometers to about 2500 micrometers, adiameter in a range from about 50 micrometers to about 200 micrometers.20. The thermoplastic composition according to claim 1, including ameans for channeling heat away from said thermoplastic matrix.
 21. Thethermoplastic composition according to claim 1, including materialshaving a heat capacity that exceeds that of said semi-crystalline resin.22. The thermoplastic composition according to claim 1, wherein saidthermoplastic composition is a product that functions in a tribologicalenvironment.
 23. The thermoplastic composition according to claim 22,wherein said product is a bearing.
 24. The thermoplastic compositionaccording to claim 22, wherein said product is a thrust washer.
 25. Thethermoplastic composition according to claim 22, wherein said product isa seal ring.
 26. A thermoplastic composition, comprising a thermoplasticmatrix that includes a resin and filler materials wherein said fillermaterials includes a combination of fibers and a thermally conductivelubricant, for improving tribological performance of thermoplasticmaterials.
 27. The thermoplastic composition according to claim 26,wherein said thermoplastic composition has a glass transitiontemperature that exceeds a bulk system temperature of surfaces of matingcomponents in a tribological environment, in the absence of frictionalheating.
 28. The thermoplastic composition according to claim 26,wherein said resin is semi-crystalline.
 29. The thermoplasticcomposition according to claim 26, wherein said thermally conductivelubricant includes boron nitride powder.
 30. The thermoplasticcomposition according to claim 26, wherein said thermally conductivelubricant includes metallic particles.
 31. The thermoplastic compositionaccording to claim 26, wherein said fibers are selected from a groupthat includes glass, aramid, carbon, and ceramic.
 32. The thermoplasticcomposition according to claim 26, wherein said thermoplasticcomposition is a product that functions in a tribological environment.33. A process for forming a product that functions in a tribologicalenvironment comprising the steps of: compounding a thermoplasticcomposition including a thermoplastic matrix that includes a resin andfiller materials wherein said filler materials includes a combination offibers, at least one lubricant, and thermally conductive material, forimproving tribological performance of thermoplastic materials; andmolding said compounded thermoplastic composition into a product. 34.The process for forming a product according to claim 33, wherein saidthermoplastic composition has a glass transition temperature thatexceeds a bulk system temperature of surfaces of mating components in atribological environment, in the absence of frictional heating.
 35. Theprocess for forming a product according to claim 33, wherein said stepof compounding includes said step of compounding includes single screwextrusion
 36. The process for forming a product according to claim 33,wherein said step of compounding includes twin screw extrusion.
 37. Theprocess for forming a product according to claim 33, wherein said stepof compounding includes batch mixing.
 38. The process for forming aproduct according to claim 33, wherein said step of molding includesinjection molding.
 39. The process for forming a product according toclaim 33, wherein said step of molding includes compression molding. 40.The process for forming a product according to claim 33, wherein saidstep of molding includes extrusion molding.
 41. The process for forminga product according to claim 33, wherein said steps of compounding andmolding are performed simultaneously.
 42. The process for forming aproduct according to claim 33, wherein said lubricant includespolytetrafluoroethylene.
 43. The process for forming a product accordingto claim 33, wherein said lubricant includes silicone resin modifier.44. The process for forming a product according to claim 33, whereinsaid thermally conductive material includes metallic particles.
 45. Theprocess for forming a product according to claim 33, wherein said fibersare selected from a group that includes glass, aramid, carbon, andceramic.
 46. The process for forming a product according to claim 33,wherein said resin is semi-crystalline.
 47. A process for forming aproduct that functions in a tribological environment comprising thesteps of: compounding a thermoplastic composition including athermoplastic matrix that includes a resin and filler materials whereinsaid filler materials includes a combination of fibers and a thermallyconductive lubricant, for improving tribological performance ofthermoplastic materials; and molding said compounded thermoplasticcomposition into a product.
 48. The process for forming a productaccording to claim 47, wherein said thermoplastic composition has aglass transition temperature that exceeds a bulk system temperature ofsurfaces of mating components in a tribological environment, in theabsence of frictional heating
 49. The process for forming a productaccording to claim 47, wherein said step of compounding includes singlescrew extrusion.
 50. The process for forming a product according toclaim 47, wherein said step of compounding includes twin screwextrusion.
 51. The process for forming a product according to claim 47,wherein said step of compounding includes batch mixing.
 52. The processfor forming a product according to claim 47, wherein said step ofmolding includes injection molding.
 53. The process for forming aproduct according to claim 47, wherein said step of molding includescompression molding.
 54. The process for forming a product according toclaim 47, wherein said step of molding includes extrusion molding. 55.The process for forming a product according to claim 47, wherein saidsteps of compounding and molding are performed simultaneously.
 56. Theprocess for forming a product according to claim 47, wherein saidthermally conductive lubricant is selected from a group that includesconductive ceramics and metallic particles.
 57. The process for forminga product according to claim 47, wherein said fibers are selected from agroup that includes glass, aramid, carbon, and ceramic.
 58. The processfor forming a product according to claim 47, wherein said resin issemi-crystalline.